Spot-welding machine



Feb. 2.6, 1929.

M. W. MOESTA SPOT WELDING MACHINE Filed 001,. 17, 1927 PatentedA Feb. 26, 1929.

A I 1,103,683 PATENT OFFICE.

MARVIN W. MoEs'rA, voir DEmaoIr, MICHIGAN.

spor-WELDING MACHINE.

Application filed Get-ober 17, 1927. Serial N'o. 226,539.

Thepresent invention pertains to a novel portable spot welding machine or suchconstruction that both electrodes may be carried from place to place and applied to the work wherevervdesired. Further, the invention includes an electrode retracting and attracting device which is operable and controlled by one of the hands of the operatorsupporting the machine.

The new construction is an improvement over that shown in my Patent No. 1,548,204 of August 4, 1925, inasmuch as the latter in-l cludes a permanently lixed electrode and movable electrode, while the new device is characterized by both electrodes being supported yin a portable carrier, withone or the electrodes movable relatively to the other. The movable velectrode is adjusted relatively to the fixed member by" the' means mentioned above.

The invention further includes a cooling system for the conductors and electrodes similar in principle to that shown in my Patent No. 1,548,204. Cooling tubes are applied to both conductors and connected to both elec. trodes and are further connected to each other so that a circulation of the cooling medium is maintained.

The invention is fully disclosed by way of `example in the following description and in the accompanyingr drawing, in which- Figure 1 is an elevation of the device partlyy in section; Fig. 2 is a section on the line 2--2 of Fig- 1 y y v Figi 3 Mis a section on the line 3 3 ofFigure 1; i

Fig. 4 is a detail vertical section showing the valve in exhaust position; and' Fig. '5 is' a similar section showing `the valve in intalreposition.

Referenceto these views will now be made by use of like characters which-are employed to` designate correspondingy parts throughout.

-The machine is built upon a frame or carrier consisting ont a cylinder 1 having bosses 2 and -3 formed at diametrically opposite points thereor. 1n the upper boss is fitted, an insulation sleeve 4, held by screws y4", which receives a metallic electrode 5.` The member 5, as shown more clearly in Figure 3 has an interior longitudinal chamber 6 into which is fitted an axial. tube 7. A. cable conductor 8 is titted into the rear end of the electrode 5 and is vformed with a head 9 whereby y itis anchored in the electrode. The electrode is again chambered asiat 10 around the conductor and terminates ina nip le 11-whichy is spaced from theconductor. n insulation tube 12 is applied over the nipple and secured thereto by a bandv 13. The tube 12 is spaced around the cable and extends for a considerable distance alongK the same. A passage 14 is drilled longitudinally of the electrode and connects the chambers Gand 10.

ln the remaining sleeve 3 is fitted a bronze sleeve 15, held by a screw 15', which provides al suitable wear surface for a cylindrical electrode holder 16 having fixedtherein a chamberedl electrode 17 similar tothe electrode 5 already described. 1t will be seen by reference to Figure l that the electrode 17 is equipped with a cable conductor 1 8 and a surrounding conduit 19. The interior construction of the electrode 17 is the same as that lof the electrode 5. Elbows 20 are threaded 12 and 19 and the electrodes 5 and 17. If for? example watervunder pressure is supplied to the tube 12, it will pass `from the chamber 10 through passage 14 to the chamber Gand will not enter the inner tube 7 until running sub-1 stantially the entire length of the chamber 6.

It will then ow through elbows V2() andcoupling 22 to the electrode 5, where it will follow a course opposite that described and will inally be discharged through the conduit;19.

HA terminal 23is fitted into the electrode 17 preferably in alignment therewith.' ,Another terminal 24 is threaded into the electrode' 5 v.preferably atright angles thereto and terminating in a tip 25 in alignment with the terminal 23. The members 23 and25 may be spaced as shown in Figure 1 to permit insertion' of the work therebetween.

The cylinder 1 land sleeve 3 are -fformed' with a common slot 26 extending partially along their length for the purposeo accommodating a lug 27 extending from the slidable holderl inthe cylinder is mounted a piston28 having the lug 27 received inthe wall 'thereof'. The piston is maintaiiied under the pressure of a spring 29 which tends to retract the piston fand holder 16 from the) terminal 24 to the position shown inFigure 1. The'forward wall of the cylinder has a vent 30 which permits ,discharge of air from the cylinder when the piston wall approaches this forward wall.

A valve casing 31 is cast integral with the cylinder l and is formed with a cylindrical chamber 32 as shown in Figures 4 and 5, .The chamber containsy a Valve consisting of a. stem 33 carrying.Y heads 34 and 35 spaced by a neck 36. The casting 31 has a boss 37 formed behind the piston and communicating with an air supply pipe 38. A duct 39 is drilled through the casting to connect the interior of the boss with the valve chamber32. Another duct 40 lis drilled through the cylinder wall to establish communication between the valve chamber and the cylinder., The size and spacing of the ports 39 and 40 are such that the ports may be bridged by the neck 36 to establish communication between the air pipe 38 and the cylinder. The valve casing 31 has an exhaust port '41, the location of which is such that the .stem 36 will permit communication between it and the port -40 when the head covers the port 39 as shown in Figure 4. A pin 42 fixed in the valve casing and engageable by the inner ends of the heads 34 and 35 prevents movement of the valve member beyond the positions described with reference to Figures4 and 5 and illus' trated therein.

The stem 33 is extended lengthwise 'of the cylinder l 'and is guided in an ear 43 formed at the forward end of the cylinder.y The extremity of the stem is in the nature of a p button 44 which is so positioned between the sleeves 2 and 3 that it ma be engaged by at least one of the hands hol ing the sleeves. A

' spring 45 attached at one end tothe stem 33 and having its other end bearing against the casing 32 normall .moves the valve to the po-` sition shown in igure 4. l

This position of the valve connects the cy inder with the exhaust port 41 and obstructs the inlet port 39, so that' the sprin 29'is free to retract the piston 28 and movab e electrode 17 to the positionA 'shown in Figure 1. The tool may now be positioned so that the area mames to be welded will be received between the ter-l minals 23 and 24. The rod 33 is now pushed inwardly by one of the fingers of the operator whereby the valve is carried to the position shown in Figure 5. The vair supply-port 39 is now in communication with the cylinder port 40 and the exhaust'port' 4l is obstructed by 4thehead 34. The compressed air which enters this cylinder moves the piston forwardly so that the terminal 23 is brought into engagement with one surface of the work while the tip 25 engages the other surface.- Current is nowl supplied to the terminals by any suitable switching device lwhich may function automatically on adjustment -of the valve.- In fact the source of current may be permanently connected to the cables 8 and 18 so that the circuit will be completed only when the members 23 and 25 engage the obgect to be welded.

Althougha specic embodiment of the invention has been illustrated and described, it will be understood that various alterations in 'the details of construction may `be made without departing from the scope of the invention as indicated by the appended claims.

yin one 'of said holders, a movable electrode supported by the other holder, a piston slidable in said cylinder and connected to said movable electrode, a valve controllin flow of pressure vfluid to and from said cy inder, and a control element adapted to actuate said valve.

In testimony whereof I aiix m signature.

" MARVIN W. OESTA. 

